SQL Template Strings

[knpwrs]

One of my favorite libraries from the node world is sql-template-strings. It allows users to take something like this:

pg.query('SELECT author FROM books WHERE name = $1 AND author = $2', [book, author])

And instead write this:

pg.query(SQL`SELECT author FROM books WHERE name = ${book} AND author = ${author}`)

Notice the placement of the book and author variables -- they are placed inline inside the query. sql-template-strings handles creating a prepared statement and ordering the parameters for query execution.

sqlx reminds me a lot of the first snippet, with the primary additional benefit being that we can get type-safety inferred from the query (which on its own is very cool!). I don't know a lot about Rust macros, but I was wondering if it would be possible to take the sqlx macro a step further and additionally implement sql-template-strings-style inline parameters.

Edit:

Here's another example from the sql-template-strings README showing the benefit when a lot of parameters are used:

db.query(
  'INSERT INTO books (name, author, isbn, category, recommended_age, pages, price) VALUES (?, ?, ?, ?, ?, ?, ?)',
  [name, author, isbn, category, recommendedAge, pages, price]
)
// is better written as
db.query(SQL`
  INSERT
  INTO    books
          (name, author, isbn, category, recommended_age, pages, price)
  VALUES  (${name}, ${author}, ${isbn}, ${category}, ${recommendedAge}, ${pages}, ${price})
`)

[mehcode]

I currently would like to do a bit in this area. Several things I'd like to "solve" ( some only in the macro variant ) about bind parameters.

• Normalize ( and allow on any db ) ? vs ?1 vs $1.
• Normalize ( and allow on any db ) @Name vs ?name vs $name ( e.g., query!(" ... ?name ", name=value) like println! ). Note that this would enable what you want given Propose implicit named arguments for formatting macros rust-lang/rfcs#2795 ( which has been accepted ).

The next step is to figure out an ergonomic method for batch insertions..

[scull7]

Are only the positional "?" parameters supported at this point?

Ah, sorry I did not see the following issue:
#199

[mehcode]

I'm going to close this for now. We've since decided to not implicitly touch the query string. So unfortunately stuff like I mentioned in the above comment isn't directly possible.

---

We feel that placeholder ( ?, @p1, $1 ) abstraction is the job of a query builder or ORM that may go on top of SQLx.

With that said, we are planning on adding a low-level dynamic query builder in the near future that would allow this.

---

I do want to explore query builders at some future but that's not on even our long-term roadmap which is why I'm closing this issue. I do still like the idea expressed in the opening. I feel it might be cool for someone to do a Maud ( https://maud.lambda.xyz/ ) style DSL using SQLx which can do stuff like that.